Process of detinning.



110.831,.223x PATENTED SEPT. 18, 1906v K. GOLDSGHMiDT & J. WEBER.PROCESS OF DETINNING.

APPLICATION FILED JUNE 29,1905.

www a Mf/Mm SAT-ES PATEN oFFIoE.

KARL sorinscsihnr inn JOSEF WEBER, or ssssaoseuariuuri,

user/rim. ASSIGNORS To FIRM TH. GQLDSUHMIDT, or ESSEN- on-isnnuns,GERMANR- A senor-respeoat-mums. s y I are. esisss.

Specification of Letters Patent.

Patented Sept. 18, mos.

Aoplicatiou filed June 29, 1966i Serial No. 267.579,

2'0 @513 whom it may concern Be it known that we, KARL GOLDSCHMIDT anddoses WEBER, subjects of the King of Prussia, German Emperor, andresidents of @ur invention consists insubjecting the tinscraps in iscompressed state m e closed vessel to the action of chlorin as and ineltering the pressure in the vesselor receptacle When'the reaction ofthe chlo'rin on the scraps 'ilisiiife place. A chief point of ourinvention is to submit the scrap'sfto the action of.

- chlorin in a firmly-com ressed state. It has been found that the clorin gas enters into the narrowest and the most closed spaces be tweenthe compressed tin scraps and'mixes' easily with the air containedtherein, so that even between the closely-packed surfaces of the tinscraps e suficient action'of the chlorin gas takes place. Thechlorin'gas is not employed in a pure state, but mixed with neutral orinert gases, as dry air, and so on.

' I It is of importance to avoid in the process high tern eratures inthe mass of the in scraps an to use the tin scraps in a well-driedstete. By this process we get the iron Waste perfectly detinned and witha fine smooth grsv surface. I v

."lhe apparatus used in this process is illustrated in the accompanyingdrawing in a vertical cross-section.

The receptacle for the compressed tin scraps is marked a and is ofcourse made of s.

material which is not infected by chlorin gas '0'." anhydrous chloridof. tin. Preferably an iron vessel is used. The-tin scraps are'me-.chanically compressed, so that they form bundles s, and the rece taclea is filled with these compressed bun les 18 of tin scraps. The bundlesare compressed and of suchasize that they can afterward be directiy usedin steel works. These bundles may converr,

. iently be, for instance, forty centimeters by sixty centimeters inwidth and length and eight-fourteenths of a centimeter in h'ei ht,

so that they have aweight from aboutv y to sixty lnlo rams. in order tofacilitate the filling oh the vessel, the packets are obtained? broughtin baskets, and thme baskets,

i with the bundles of compressed tin scraps,

are tli'en'introduced into t e yessel.

After the apparatus a has been filled with, the bundles of tin scrapsand the apparatus, being under ordinary pressure the chlorin gas isadmitted from above through the pipe.

The chlorin gas being under a certain overpressure above ordinarypressure. is at first diffused in the upper free space n over thebaskets d and is there mixed with the air I of the apparatus. Themixture of chloringas and air acts upon the baskets or bundles ofcompressed tin scraps, and the chlorin gas is now constantly absorbed bythe tin on the tin scraps. Assoonas the chlorin gasv is absorbed and hasformed chlorid of tin naturally new partsof chlorin gas come in reactionand are mixed with the air contained in the vessel, and so the mixtureis again enriched by freshly admitted and diffused chlor'in gas.- Nowthe process is so guided that the pressure in the vessel is augoriented,so that at the end of the operation .the overpressure-for instance, ofone at-v mosphere above the ordinary pressure-is B the increasing ofthcpressure in'the vessel t echlorin gas comes in contact with all thesurfaces of the tin scraps, so that even between the most closely packedsurfaces of the tin scraps asufiicicnt actionof the chlorin gas andformation of chlorid of tin takes place. At the commencement of theoperation the chlorin gas when passing over the firmly-compressed Wastewill naturally be eagerly taken up by the tin on accountof its greataiiinity for the latter; but as soon as. the leading action ofthe'chlorin gas has taken c place at the easily-accessible parts of thetin scraps the reaction will slow down, and so the parts of the tinscraps-Which are firmlycompressed and where the surfaces are in closecontact with one another might easily remain unafl'ectcd; but themixture of chlorin and air is driven by the increasing pres-- sure intothe :narrowest channels or;- inter.-

stices of the tin scraps, so that the whole surfaces are-detinned. ,Itis easily to be seen roe that the increasing'of the ressure in thevessel is of greatimpcrtance or finishing the detinning processcompletely and in a short time. v

It is important to avoid agreat increased 105 temperature.

Instead of increasing the ressure in the vessel it is possible todiminis the same and then to increase it again. process can be carriedout in the f0 lowing manner: At first the vessel when filled with tinscraps is closed and then evacuated by an air-pump connected with thepipe f. (Not shown.) Then the chlorin gas is mixed with air admitted tothe vessel through the pipe 2, so that at least the common ressure inthe vessel results or so that a sligl it overpressure is obtained. Thenwe can again pum out the mixture of air and chlorin gas or t e air whichfills the vessel after the chlorin gas has been absorbed by the tin, andwe may intro duce again chlorin gas mixed'with air, into the vesseluntil the common pressure in the vessel results.

It is of great importance to use the tin scraps in a stron ly-compressedstate, which can of course )e effected b mechanical means only. Then itis ossiblh to pack the tin scraps in' strong bum les of fifty to sixtykilograms-for instance, into baskets or crates-so that the vessel inwhich the process is carried out containsseveral tons of tin scraps.Thereby the cost of labor, which is an essential factor in all suchprocesses, is greatly reduced.

The stronger the tin scraps have been compressed the stronger must bethe change in pressure, because only under this varied For exam le, the

pressure the chlorin gas will easily enter the narrowest intersticesorchannels and change the tin quickly and completely into tetrachloridof tin. As already said, the res'sure may be decreased or increased in te process, but always a varying of the pressure must take place.

By the term inert gas used in the de- 1 scription' and in the followingclaims we i mean a gas which does not attackthe scrap j or chlorin orany of the products thereof during the process of detinnin Having thusfully described the nature of our invention, what we desire to secure byLetters Patent of the United States is 1. Process of detinning, whichconsists in compressing loose tin-scrap and treating said compressedscrap in a vessel with chlorin gas.

2, Process of detinning, which consists in compressing loose tin-scrapinto compact bun les of relatively small size, and treating said bundlesin a vessel with chlorin gas.

3. Process of detinning, which consists in compressing loose tin-scrapand treating said compressed scrap in a vessel with chlorin gas I incombination with an-inert gas.

4. Process of detinning which consists in 1 com ressing loose tin-scrapinto compact bun les of relatively small size, and treating said.bundles in a vessel with chlorin gas in combination with an inert gas.

5. Process of detinning, which consists in" treating tin-scrap in avessel with chlorinjgas in combination with an inert gas, and-alteringthe pressure in the vessel during the detinmn 9% Process of detinning,which consists in treating tin-scrap in a vessel with chlorin gas incombination with aninert as, and increasing the pressure in the vesseduring the detinning.

10. Process of detinning, which consists in treating tin-scrap in avessel-Withchlorin gas 4 o r 1 7 pressure 111 the vessel dur= e pressurein the vessel urin combination with an inert as,andincreasing thepressure in the vesse during the detinning and then diminishing it. p

11. Process of detinning,-which consists in compressing'loose tin-scrapand treating said compressed scrap in a-vessel withchlorin gas, andaltering the pressure in the vessel during the detinning. Y

12. Process of detinning, which consists in compressing loose tin-scrapand treating said compressed scra in a vessel with chloringas, andincreasing t 6 pressure in the vessel uring the detinning.

13. Process of detinning, which consists in compressing loose tin-scrapand treatingsaid compressed scrap in a vessel with chlorin as, andincreasing t e pressure in thevesseluring the detinnin and thendiminishing it.

14.. Process 0 detinning, which consists in compressing loose tin-scrapand treating said compressed scrap in a vessel with chlorin gas, incombination with an inert gas, and altering the pressure in the vesselduring the detinnin 15. Process of detinning, which consists incompressing loose tin-scrap and treating said compressed scrap in avessel withchlorin gas,

in combinationwith an inert "as, and increasing the pressure in thevessel tinnin p 16. Process of detinning, which consists in compressingloose tin-scrap and treating said compressed scrap in a vessel withchlorin gas, in combination with an inert gas, and increasing theressure in the vessel during the dctinning an then diminishing it.-

In witness whereof we have hereunto set our hands in. the resence of twowitnesses. RL GOLDSCHM-IDT. JOSEF WEBER. Witnesses:

' WILLIAM ESSENWEIN.

H. SCHUCHARDT.

during the de-

